The present invention relates generally to medical devices, and more particularly, to apparatus primarily intended for peritoneal dialysis or other medical treatment of humans or animals, wherein the administration of fluids in relatively large quantities is required for such treatment.
Today, so-called peritoneal dialysis is becoming increasingly common. With this form of treatment, a fluid is periodically or continually introduced into the peritoneum and then withdrawn therefrom. Toxic substances enter the fluid while it is in the peritoneum and are removed when the fluid is drained.
As in the administration of other fluids for medical use, a chronic problem in the industry has been to insure that the "spike" which forms one end of the administration apparatus is in an aseptic condition and is maintained in this condition, especially just prior to insertion thereof into a bag, bottle or other container for the dialyzing fluid, so that fluid which is sterile or aseptic as packaged does not become contaminated just before or during administration.
Some methods of approaching this problem in the past have included removal of the spike from a protective sheath or the like before insertion into the bag or the like. In such an apparatus, there is always the possibility of contamination of the spike between the time it is removed from a sheath and sterilized and the time it is inserted into the bag or other container for fluid. Futhermore, there is also the chance that contamination will occur by reason of the entry of the spike into the bag or bottle, that is, by contact with contamination existing on the exterior pierceable surfaces of the bag or the like.
Other methods have been proposed in which the spike may be sterilized by radiation or by sterilizing fluids, but wherein the sterilizing fluid may be transferred from the spike into the receptacle for the dialyzing fluid or other fluid to be administered. Bearing in mind that spikes are hollow, it will be appreciated that the possibility of filling the interior of the spike with a fluid other than the dialyzing fluid can create its own problems, particularly in parenteral fluids administration.
According to the present invention, an improved apparatus and method is provided for sterilizing a spike or like portion of a dialysis apparatus without compromising the sterility of the system as a whole and also without the need to introduce foreign fluids themselves as contaminants of the fluid contained in the bag or bottle, or to change the composition of the final fluid administered to the patient.
According to the invention, the bag or like container for the administered fluid is subdivided into a major chamber and a smaller chamber which is not originally in communication with the first chamber. In a preferred form, the first or larger chamber contains a fluid which is not suitable for administration until mixed with the contents of the second chamber, and the second chamber contains a fluid not suitable for administration until mixed with the contents of the first chamber. For example, it may contain saline or like solution, in much greater concentration in the chamber of reduced volume and much lower concentration in the chamber of larger volume. According to the invention, the smaller chamber includes a pierceable or rupturable portion with a pierceable or rupturable membrane forming a part thereof and adapted, when pierced or otherwise ruptured, to maintain a fluid-tight seal. The smaller chamber is also arranged for bellows like or axial contraction when desired, and is arranged so that either a portion thereof, an insert therein, or the spike itself may be forced into the larger chamber through a second or subdividing membrane, with the dual result that the fluid previously contained in the smaller chamber is forcibly expelled from the first chamber into the enlarged chamber wherein dilution takes place, the spike having been sterilized by its initial contact with the concentrated fluid in the first chamber.
In another embodiment, the fluids are different but compatible, and the sterilizing fluid is non-objectionable from the standpoint of administration to the patient.
Inasmuch as the fluids are always both compatible and suitable for the intended purpose when admixed, the needle may be sterilized, the entry of foreign matter is completely prohibited, and the need for providing complex directions concerning sterilizing procedures or the like may be obviated.
According to a preferred form of the invention, the receptacle for the fluid comprises a bag or the like having a neck portion extending outwardly therefrom and sealed off by a subdividing membrane which forms the inner end wall of the smaller chamber. The smaller chamber likewise includes an exterior end wall or membrane and flexible side wall portions. Preferably it also includes a combination interior needle sheath, guide and holder permitting desired safety and operational features, as will appear. Bayonet locks or the like may also be utilized to insure retention of the needle with respect to the bag as a whole. The administered fluid is preferably a saline solution or the like, but according to the invention, a number of fluids have been found which quite surprisingly serve as disinfectants or sterilizing agents in high concentrations and yet which are compatible with water or other fluids so as to provide appropriate concentrations of a dialyzing or like solution.
In view of the need for improved apparatus for peritoneal dialysis or other medical applications, it is an object of the present invention to provide an improved combination fluid storage receptacle and sterilizing apparatus.
Another object of the invention is to provide an improved method of sterilizing spikes or like devices, used in medical fluid administration, particularly those adapted for simple manufacture at low cost and ease of operation.
Another object of the invention is to provide a method of sterilizing a spike or the like which involves immersing the spike in a solution having a first ingredient concentration for a period of time sufficient to permit reduction of the bacteria or other contamination count to a medically acceptable level, and subsequently using the fluid just utilized to sterilize the needle as an additive or diluent for another volume of the same or similar fluid to create a single solution which may be administrated through the thus-sterilized spike.
Another object of the invention is to provide a bag or like fluid administration apparatus having an enlarged first storage chamber a second sterilizing chamber of reduced volume, a pierceable subdividing membrane separating the two chambers and a pierceable membrane disposed on and forming a part of the exterior of the reduced volume chamber, with the smaller chamber being, in its extended condition, just larger axially than the length of the associated spike or like device.
Another object of the invention is to provide a medical apparatus having a spike or like device adapted to pierce a container membrane, a bag having first and second chambers isolated from each other by a pierceable or rupturable membrane, first and second fluid chambers and a needle locating device contained in the smaller of the chambers and with the smaller chamber being filled with a sterilizing fluid, and with the larger chamber being filled by a compatible fluid for administration to a patient.
A still further object of the invention is to provide a method of sterilizing a spike which involves transiently immersing it in a solution adapted for peritoneal dialysis, with the solution being a concentrated saline solution, a diluted form of which is adapted for administration for peritoneal dialysis.
The foregoing and other objects and advantages of the invention are achieved in practice by providing a bag or like fluid container unit adapted to receive and hold a hollow spike and tube, with the container being subdivided into a first, larger contents container and a much smaller sterilizing fluid container, with the two containers having common exterior walls and being separated from each other by a pierceable or rupturable subdividing membrane, with the smaller chamber being generally in the form of a cylindrical neck which is axially collapsible so that a needle may be positioned and held in the smaller chamber for sterilizing, and subsequently moved axially, along with a portion of the chamber walls, so as to pierce the membrane and expel sterilizing fluid into the larger chamber, and then permit the mixed fluids to flow through the hollow needle to the patient. The larger chamber is preferably filled with the same fluid as that contained in the smaller chamber, except that the fluid in the smaller chamber is of a much different concentration, or in the alternative, two compatible fluids are used, and selected so that the first will sterilize the needle but will also mix with the other fluids so that the combined or mixed fluid may be administered to the patient without harm.
The exact manner in which the invention achieves these and other objects and advantages will become more clearly apparent when reference is made to the following detailed description of the preferred embodiments of the invention set forth by way of example, and shown in the accompanying drawings, wherein like reference numbers indicate corresponding parts throughout.